It is known that the process of drilling and cutting creates a great deal of heat where the dental cutting tool, known as a "bone bur", cuts into the bone and causes dessication of the bone. The heat generated by the bur causes dessication and destruction of the bone. It is therefore desirable to apply cooling to the bur and the bone during the drilling and cutting process. It is also desirable for the bur to have a readily removable distal end so that the cutting tip can be inexpensively replaced when worn.
It is known from the prior art to provide a water channel in a dental bur, as shown in U.S. Pat. No. 3,393,452, which shows a dental bur having a bore through its shank and through the cutting tip of the bur extending to its distal end for admitting cooling water to the area of the tooth being drilled or cut. This arrangement, however, has the drawback that it cannot be applied to dental burs of very small diameter, such as for example 1.3 mm or less, since practical technology is not available for forming a long bore of such a small diameter. Burs of such small diameter are often required for drilling and cutting teeth. U.S. Pat. No. 5,100,322 shows a water-cooled dental tool which has an internal hollow space and holes cut transversely through the cutting tip of the tool for admitting a stream of liquid or air for cooling the drilling operation. The dental bur according to the last mentioned patent relies on only cooling liquid sprayed against the exterior of the cutting tool. The holes in the tool are, however, easily filled with cutting material from the tooth, so that the cooling action is lost.
It is accordingly an object of the present invention to provide a liquid-cooled dental bur which does not have the drawbacks of the known dental burs, and which provides effective cooling also for dental burs of quite small diameters.
It is a further object of the present invention to provide such a bur in which the cutting tip is easily removed and replaced.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.